//copy chars form str1 to str2.
void copyString(char *target, char *source){
 while(*source){
 *target = *source;
 source++;
 target++;
 }
 *target = '\0';
}
 
int compareString(char *string1, char *string2){
 while(*string1==*string2){
 if ( *string1 == '\0' || *string2 == '\0' ){
 break;
 }
 string1++;
 string2++;
 }
 if( *string1 == '\0' && *string2 == '\0'){
 return 0;
 }else{
 return (*string1 - *string2);
 }
}
 
 
void stringConcatenate(char *string1, char *string2){
 while(*string1!='\0'){
 string1++;
 }
 while(*string2!='\0'){
 *string1=*string2;
 string1++;
 string2++;
 }
 *string1='\0';
}